Effect of ubiquinone-10 on fluctuation of beating rhythm of cultured myocardial cell sheets.

Effects of ubiquinone-10 (UQ-10) on fluctuation of beat time intervals and on beat frequencies were investigated in cultured ventricular myocytes obtained from mouse fetuses and quail embryos. Fluctuation rates of beat time intervals of mouse and quail myocardial cell sheets growing in the culture medium supplemented with 10% fetal bovine serum increased significantly to 1.2-fold and twice, respectively by removing serum from the medium. Beat frequencies of the cell sheets also significantly decreased simultaneously with the increase in the fluctuation rates. However, such changes of beating states were almost completely recovered within 10 min by addition of 100 microM UQ-10 as an isotonic lecithin emulsion to the medium. The addition of UQ-10 also significantly increased intracellular ATP content in the cell sheets concomitantly. These results suggested that UQ-10 circulating in serum may participate in the maintenance of regular and rhythmical beating of myocardial cells, presumably through stimulating intracellular ATP generating systems.